Midterm 2 Review

Fault formation

rock bends elastically, then cracks. Cracks link to fracture which causes sliding and generates vibration (earthquake)

Biochemical sedimentary rock

sedimentary rock formed from material (such as shells) produced by living organisms

Where do most earthquakes occur?

seismic belts; along plate boundaries

How to detect earthquakes?

seismometer

syncline fold

-bends downward (U shape)

Why do waves refract as they approach the shore?

Friction wth the seafloor

Ripple marks

Small waves of sand that develop on the surface of a sediment layer by the action of moving water or air.

Uplift

Vertical rise of a mountain belt

Characteristics of lava flow are dependent on?

Viscosity

Where do rapids develop?

When a stream flows down steep gradients

Modified Mercalli Intensity Scale

characterizes earthquakes size based on ground shaking and of damage

Large gyres

circulate water around each basin

4 major classes of sedimentary rocks

clastic, biochemical, organic, chemical

Speleotherms

consist of stalactites, stalagmites, limestone columns when limestone percipitates out of water

Ephemeral streams

dry up for part or most of the year

hydrothermal metamorphism

due to the circulation of hot water in oceanic crust at mid-ocean ridges

clastic sedimentary rock

eroded grains accumulate and through lithification, loose sediments becomes rock

Blueschist

form in accretionary prisms

fold-thrust belt

form on continental edge of collisional and convergent boundaries

Veins

form when minerals precipitate out of water while passing through joints

extrusive igneous rock

formed from erupted lava

intrusive igneous rock

formed from magma that froze in the Earth

pyroclastic debris

fragmented material that sprayed out of a volcano (varies in size), fall from air or flows down the sides of the volcano

recharge area

Any area of land allowing water to pass through it and into an aquifer.

Deformation produces:

geological structures

Clastic rock classification

grain size

Fragmental igneous rock classification

grain size

Crystalline igneous rock classification

grain size + composition

A'A' lava

lava that hardens into rough, jagged rocks with a crumbly texture

Basaltic lava

low silica, flows easily

Low-grade rocks

low temp

Wetland features

marshes or mangrove swamps

dynamic metamorphism

metamorphism that occurs along faults, plastic shearing

Index minerals

minerals used to estimate the temperature, depth, and pressure at which a rock undergoes metamorphism

Felsic magma is

more viscous than mafic

Orogeny

mountain building event

Joints

naturally formed cracks in rocks (under brittle conditions)

intraplate earthquakes

occur within the interior of plates

dome fold

overturned bowl

Active continental margins host. . .

plate boundaries

Why are rivers becoming a vanishing resource

pollution, damming and overuse

Wadati-Benioff zone

the band of earthquakes in a subducting plate

shock metamorphism

the changes that can occur in a rock due to the passage of a shock wave, generally resulting from a meteorite impact

Minimize volcanic consequences

-assessment maps -evacuation plans

Eruptions occur

-crater at summit -fissures (magma rising through cracks)

Rate Magma Cools

-depth of intrusion -shape and size -groundwater circulation

Volcanic eruption hazards

-overrun towns -ash blanket -lava incinerates towns -landlsides +lahars bury land -earthquakes rupture structures -tsunamis wash away the coats -gases suffocate people and animals

metamorphic foliation

-preferred orientation -compositional banding

What causes deformation?

-stress -compression -tension -shear

What are the differences among coasts

-tectonic setting -sea level rising or falling - sediment supply - clear water

Eruptive style depends on

-viscosity -gas content

Cross bedding

Structure in which relatively thin layers are inclined at an angle to the main bedding. Formed by currents of wind or water.

Coriolis Force

The apparent force, resulting from the rotation of the Earth, that deflects air or water movement.

Reef bleaching

The death of algae that live in coral polyps is called _____ and may be the result of global increases in seawater temperature.

What creates deep currents?

Upwelling and downwelling

When does a flood occur?

When more water enters the stream than the channel can hold

When does earthquake/seismic activity happen?

When rocks slip during faulting

Where does groundwater flow?

Wherever a hydraulic gradient exists (from under pressure to where its not under pressure)

Does groundwater exit the ground on its own at a spring?

Yes

Diagenesis

a collective term for all the chemical, physical, and biological changes that take place after sediments are deposited and during and after lithification

longitudinal profile of a stream

a concave-up curve

What happens when water is pumped too quickly out of a well

a cone of depression

oblique fault

a fault where the motion is diagonal. A combination of vertical and strike-slip movement

Mud cracks

a feature in some sedimentary rocks that forms when wet mud dries out, shrinks, and cracks

Orogen

a linear range of mountains

accretionary prism

a mass of sedimentary material scraped off a region of oceanic crust during subduction and piled up at the edge of the overriding plate.

Evaporites

a natural salt or mineral deposit left after the evaporation of a body of water.

thermohaline circulation

a result of variatons in temepratue, salinity, density

thrust fault

a reverse fault in which the hanging wall slides over to the foot wall.

strike-slip fault

a type of fault where rocks on either side move past each other sideways with little up or down motion

reverse fault

a type of fault where the hanging wall slides upward; caused by compression in the crust

Active faults differ from inactive faults in that

active faults will have future movement while inactive faults ceased being active long ago

Cone of depression

an area lacking groundwater due to rapid withdrawal by a well

anticlines fold

arch-like

Sedimentary structures

bedding, cross bedding, graded bedding, ripple marks, dunes, and mud cracks

What are streams?

bodies of water that flow down channels and drain land surface

basin fold

bowl-shaped

Shields expose. . .

broad areas of Precambrian metamorphic rocks

How to protect beach property

build groins, jetties, breakwaters, and seawalls

Delta

A landform made of sediment that is deposited where a river flows into an ocean or lake

Caldera

A large, bowl-shaped depression formed by the collapse of part of a volcano.

Richter scale

A scale that rates an earthquake's magnitude based on the size of its seismic waves.

normal fault

A type of fault where the hanging wall slides downward; caused by tension in the crust

artesian well

A well in which water rises on its own because of pressure within the aquifer

Permeability

Ability of rock or soil to allow water to flow through it

What determines porosity?

Amount of open space in rock or sediment

effusive eruption

An eruption that yields mostly lava, not ash.

Graded bedding

Bedding in which the particle sizes become progressively heavier and coarser toward the bottom layers

How can earthquake hazards be reduced?

Better construction practices and zoning, and educating people on what to do in case of an earthquake.

How do water channels grow?

Downcutting and headward erosion

Precambrian Era

Earth's first era that began 4.6 billion years ago that includes creation of the Sun, Earth, the atmosphere, oceans and life

Where do mountains occur?

Elongate ranges-mountain belts or orogens

Volcano shape is dependent on?

Eruptive style

Magma Composition Range

FIMU Felsic Intermediate Mafic Ultramafic

True or false: it is possible to pinpoint the exact time and place an earthquake will occur?

False

Alluvial fans

Fan-shaped deposits of sediments dropped by streams flowing out of mountains (canyon mouths)

What builds ocean waves

Friction from where the wind shears across the surface of the ocean

What generates tides?

Gravitational pull of the moon

What is subsurface water called?

Groundwater

What causes uplifts of rifts?

Heating of the lithosphere.

Surface waves

L and R waves (surface of the Earth)

Partial Melting-Magma

More felsic

Where can you find belts of metamorphic rocks

Mountain ranges

Can streams cut below the base level?

No

Pore collapse

Occurs if water is drawn out of aquifer and replaced with air. This process permanently decreases the ability to hold groundwater.

What is the larges known volcano and where is it?

Olympus Mons-Mars

How have regions lost their groundwater supplies?

Overuse or contamination

Body waves

P and S waves (interior of the Earth)

Where do wide continental shelves form?

Passive-margin basins

Origins of igneous rock

Plate tectonics (magma forms at volcanic arcs and convergent boundaries)

Epicenter

Point on Earth's surface directly above an earthquake's focus

organic sedimentary rock

Sedimentary rock that forms from the remains of plants or animals.

What determines the location and orientation of caves

soluble beds and joints

stick-slip behavior

stop-start movement along a fault plane caused by friction, which prevents movement until stress builds up sufficiently

Water table

surface in the ground where pores contain some air and below where pores are filled with water

Slow-onset flood

take time to develop and tend to happen seasonally

Viscosity depends on?

temperature and composition

Cooling time controls

texture

Glassy igneous rock classification

texture and gas bubbles

discharge area

the location where groundwater flows back up to the surface

preferred orientation

the parallelism of inequant grains in a metamorphic rock

Hypocenter (focus)

the place where fault slip occurs

Metasomatism

the process by which a rock's overall chemical composition changes during metamorphism because of reactions with hot water that bring in or remove elements

orogenic collapse

the process in which mountains begin to collapse under their own weight and spread out laterally

Metamorphism

the process in which one type of rock changes into metamorphic rock

Downcutting

the process in which water flowing through a channel cuts into the substrate and deepens the channel relative to its surroundings

elastic rebound theory

theory that rocks that are strained past a certain point will fracture and spring back to their original shape

Stream's capacity

total quantity of sediment carried by a stream

discharge of a stream

total volume of water passing a point along the bank in a second

What are volcanoes?

vents where lava, debris, gases and aerosols, erupt at Earth's surface

What happens during the hydrologic cycle?

water infiltrates the ground and fills the pores and cracks in rock and sediment

Rocky coasts features

wave-cut platforms and sea stacks

How do engineers prevent floods?

building reservoirs and levees

Why does magma rise?

buoyancy and pressure; less dense than surrounding rock

How do geologists classify rock and sediment

by permeability

Fluvial erosion

can bevel landscapes to a flat plain

causes of metamorphism

changes in heat and pressure, differential stress, hydrothermal fluids

Dissolved ions

charged atoms or molecules in a water solution to form cement or veins

Where do coral reefs form?

clear, warm coastal waters in tropical areas

explosive eruption

clouds and debris

Braided streams

consist of a series of intertwined channels that are overloaded with sediment

What causes underground caves?

when limestone dissolves just below the water table

dynamothermal metamorphism

when rocks undergo heating and shearing during mountain building

Where does flow velocity slow

when water comes in contact with the walls or bed of the channel

Geological configurations that lead to spring formation

when water reached the surface through a fracture or porous layer (usually along faults)

Meandering stream

curves back and forth across a floodplain

Tides

daily rise and fall of sea level

What does groundwater contain?

dissolved ions

passive continental margin

do not coincide with a plate boundary

Current Theory of Earthquake Formation

elastic rebound

Ordinary well

fills with water because it penetrated ground below the water table

Darcy's law

flow rate depends on permeability and the hydraulic gradient

2 classes of metamorphic rocks

foliated and non-foliated

tectonic foliation

grains flatten, rotate, or grow so that they align parallel with one another

Earthquake damage results from:

ground shaking, landslides, sediment liquefaction, fire, and tsunamis

Flash floods

happen very rapidly

High-grade rocks

high temp

panhoehoe lava

highly fluid lava, smooth, ropy texture due to the abundant gas content, basaltic

Dunes

hills of sand formed by the wind

Non-foliated

hornfels, marble, quartzite

Seamounts and oceanic form above . . .

hot spots

What releases hot water to the Earth's surface

hot springs and geysers

Aquitards

impermeable

Intermediate-grade rocks

in between extreme temps

How does earthquake energy travel?

in the form of seismic waves

monocline fold

is a step-like

Streams erode. . .

landscape and carry the resulting sediment

Bedding

layering visible in rocks that results from the settling of particles during deposition

Magma

liquid rock under Earths surface

Lava

melted rock that reaches Earth's surface

thermal metamorphism

metamorphism caused by heat conducted into rock from an igneous intrusion

burial metamorphism

metamorphism due only to the consequences of very deep burial in a sedimentary basin

What is groundwater used for?

municipal water supplies, industry, and agriculture

Where do abyssal plains develop?

old, cool oceanic lithosphere

Cratons

old, large, stable block of the earth's crust forming the nucleus of a continent.

Shield

older interior region of a continent

How is the water heated in a hot spring?

passing deep in the crust or by proximity of magma

Andestic and Rhyolitic Lava

pile into mounts at vent

What are the results of groundwater overuse?

pore collapse or saline infiltration

Aquifers

porous and mermeable

chemical sedimentary rock

precipitated from water by either inorganic or organic means

What does metamorphism involve?

recrystallization phase changes metamorphic reactions pressure solutions plastic deformation metasomatism

Stream competence

refers to the maximum particle size a stream can carry

Karst landscape

regions where abundant caves have collapsed t o form sinkholes

During brittle deformation

rocks break into 2 or more pieces

During plastic deformation

rocks change shape without breaking

grain characteristics

roundness, sorting, composition

What varies with location and depth in seawater

salinity, temperature and density

What happens during longshore drift?

sand moves alng the beach and extends outward to form sand spits.

Regression occurs when

sea level falls and the coastline migrates seaward

transgression occurs when

sea level rises migrates inland

Seismograms

shows the different times earthquake waves arrive to detect epicenter location

Karst landscape terrains

sinkholes, natural bridges, and disappearing streams

Foliated

slate, phyllite, schist, gneiss, metaconglomerate

Predicting Eruptions

-Earthquake activity -Changes in heat flow -Chnages in the shape -Emission of gas and steam

Magma Formation

-Partial Melting -Decompression -Volatiles Diffuse Heat transfer

What happens during mountain building?

-Rock undergoes deformation (change its location, orientation, shape)

Lithification

The process that converts sediments into solid rock by compaction or cementation.

metamorphic zone

The region between two metamorphic isograds, typically named after an index mineral found within the region.

stream rejuvenation

The renewed downcutting of a stream into a floodplain or peneplain, caused by a relative drop of the base level

How does water in the ocean circulate?

Through currents driven by wind

True or false: a hill or mountain produces by volcanism is also a volcano

Tru

Tru or false: human activities have led to the pollution of coasts?

True

True or false: Evidence of eruptions have been found on the moons of Jupiter and Saturn?

True

True or false: Flood basalts cover portions of the moon

True

True or false: crustal thickening occurs at mountain ranges?

True

True or false: seismologists can determine the recurrence interval for great earthquakes

True